Use of electromyography to assess pain in the upper trapezius and lower back muscles within a fatigue protocol

• Published in: Revista brasileira de fisioterapia (São Carlos (São Paulo, Brazil)) Brazil)), 2009-04, Vol.13 (2), p.144-151
• Main Authors: Candotti, CT, Loss, JF, La Torre, M, Melo, MO, Araújo, LD, Marcks, VV
• Format: Article
• Language: eng ; por
• Subjects: ORTHOPEDICS; REHABILITATION
• ISSN: 1413-3555; 1809-9246
• DOI: 10.1590/S1413-35552009005000018

Objective: The aim of this study was to investigate whether muscle fatigue indices obtained using surface electromyography and calculated in the time and frequency domains would be capable of objectively diagnosing pain and discriminating between subjects with and without pain in the upper trapezius muscle and the lower back muscles. Methods: Forty-seven individuals underwent a muscle fatigue test for thirty-five seconds at 80% of the maximal voluntary contraction (MVC), while EMG and muscle force data were recorded. The RMS value and the median frequency (MF) were calculated within consecutive one-second windows. Linear regression analysis was used to obtain the slope coefficients and the respective y-axis intercept values, which were considered to be localized muscle fatigue indices. Results: In the frequency domain, the slope coefficients were negative for both muscles, while in the time domain, the coefficient for the upper trapezius was positive and the coefficient for the lower back muscles was negative (p